Non-contacting automotive dryer releasable connection

ABSTRACT

A drying apparatus (10) for a vehicle washing system maintains blower air bags (18) a predetermined distance from the vehicle without contacting same providing forced air against the vehicle. Ultrasonic sensor (66) are provided on front and back sides of the nozzle (26) for sensing objects within a predetermined distance in combination with control circuitry. The control circuitry controls a motor (42) to retract a cord (36) to in turn raise or move out of the path of the vehicle, the air bag (18) maintaining the predetermined distance from the vehicle. The signals from each of the sensors (66) are each combined to control the motor. Releasable connections are provided between the air bag and support structure to allow releasing of control of the cord in case of emergency.

TECHNICAL FIELD

The invention relates to an apparatus for stripping fluid from asurface, such as that of a vehicle, and more particularly, to sensingthe proximity of the surface and adjusting the position of a blower airbag in response thereto.

BACKGROUND ART

Car wash systems generally include drying stations which utilizeflexible inflatable bags for removing fluid from a vehicle surface todry the vehicle. Rollers have been connected to the end portions of thenozzles of the bag to engage the surface of the passing vehicle. Such isdisclosed in U.S. Pat. No. 4,446,592, issued May 8, 1984 in the name ofMcElroy and assigned to the assignee of the subject invention.

It has become desirable to eliminate nozzle/air bag contacting thevehicle by providing a proximity sensor to sense the location of thevehicle with respect to the nozzle, and maintaining a predetermineddistance therebetween. Automotive car drying systems have been proposedwhich utilize ultrasonics to sense the distance of the vehicle from thedrying system. One such system is illustrated in U.S. Pat. No.4,995,136, issued Feb. 26, 1991 in the name of Smith. The blower bag ofthe system is positioned according to an output signal from anultrasonic imaging sensor mounted on support frame of the system. Therelative position of the blower bag is measured by a linearpotentiometer mounted to the piston which positions the blower. Thesensor output is compared with the potentiometer output to adjust thearm to control the height of the bag from the vehicle.

U.S. Pat. No. 4,949,423, issued Aug. 21, 1990 in the name of Larson etal discloses a dryer for automatic car wash equipment utilizing twosensors to maintain the nozzle within a preselected proximity range ofthe top portions of the vehicle; one sensor for detecting the proximityof a nozzle to opaque top portions of the vehicle, and one sensor fordetecting the proximity of the nozzle to transparent top portions of thevehicle. The means by which the nozzle is mounted and moved toward andaway from the vehicles vary the orientation of the nozzle relative tovertical as the nozzles move between their uppermost and lowermostpositions.

U.S. Pat. No. 4,587,688, issued May 13, 1986 in the name of Gougoulasdiscloses a proximity detector for car dryer equipment. The height ofthe dryer is adjusted by a sonar proximity detector. The sonar detectortransmits a signal and receives the reflection to detect the distance byelapsed time between the transmitted and received signals.

SUMMARY OF THE INVENTION

The invention relates to an apparatus for stripping fluid from a surfaceof an object as the object is conveyed relative to the apparatus along apath. The apparatus comprises an air distributor and a plurality ofdistributing members having first and second ends. The first end issupported by the air distributor about the path of the surface forreceiving air under pressure from the air distributor and the second endincludes the nozzle for directing the air toward the surface to stripfluid from the surface. Also included is actuator means connectedbetween the distributor and the distributor member for moving thedistributor member toward and away from the surface. Actuator controlmeans is operatively connected to the actuator means for receiving acontrol signal to control movement of the actuator means.

Also included is a releasable connector connected between the actuatingmeans and the link means for allowing separation thereof in response toa predetermined force, and a releasable connection between the linkmeans and the bag for allowing separation therebetween in response to apredetermined force. The actuator means comprises a motor having a spoolconnected thereabout with an aperture therein. The link means includes aline having a ball connector at one end for releasable connection to thespool aperture in response to a predetermined force on the link means.

FIGURES IN THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of a drying station of a car wash systemconstructed in accordance with the subject invention;

FIG. 2 is a perspective view of the supervisory sensor means;

FIG. 3 is a perspective view of the satellite sensor means;

FIG. 4 is an enlarged perspective view of the actuator means incombination with the bag;

FIG. 5 is an enlarged perspective view of the bobbin/spool of theactuator means;

FIG. 6 is a block diagram of the control means of the subject invention;

FIG. 7 is a schematic diagram of the timing means;

FIG. 8 is a schematic diagram of the supervisory means;

FIG. 9 is a schematic diagram of the receiver of the sensor means;

FIG. 10 is a schematic diagram of the motor control means;

FIG. 11 is a schematic of the transmitter of the sensor means; and

FIG. 12 is an end view of the nozzle and sensors on the vertical bag.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, a drying station or apparatus of vehiclewashing system is generally shown at 10 in FIG. 1. The drying apparatus10 is constructed for stripping fluid from the surface of a vehicle asthe vehicle is conveyed along a path 11 through a car wash system. It isto be understood that the apparatus 10 may be used to strip liquid ormaterial from any type of surface, and is not only limited to vehicles.Relative movement is provided between the surface and the apparatus 10.The drying station includes an air distributor including a fan assembly12 and an overhead duct or plenum 14. Beams 16 may be used to supportthe plenum 14 from the floor of the car wash. The drying apparatus 10further includes a plurality of air distributor members or flexible bags18, each having a generally rectangular transverse cross section. Thestation includes a plurality of vertically hanging bags 18a andsubstantially horizontally disposed bags 18b. The bags 18 are supportedby the air distributor plenum 14 in an array along the path of a vehiclepassing through the drying station in order to strip fluid from the topand side surfaces of the vehicle. Each of the bags 18 includes a baginlet end 22 connected to the plenum 14 for introducing air underpressure into the bags 18 and an outlet end 24 spaced from the inlet end22. The assembly 10 further includes nozzle members 26, which aresubstantially the same as disclosed in U.S. Pat. No. 4,446,592 discussedin the background of the invention, and incorporated by referenceherein. The length of the horizontally extending bags 18b locates thenozzle members 26 at approximately bumper height while the bags 18 areat rest. The substantially horizontally extending bags 18b havesufficient lengths so that the nozzle members 26 connected thereto willengage the oncoming vehicle. Due to the restriction at the outlet end ofthe bag 18 provided by the nozzle 26, a back pressure is created whichis greater than atmospheric pressure to keep the bags 18 in an inflatedcondition. The pressure within the bags 18 determines the flexibility ofthe bags 18. In an inflated condition, the air pressure in the bags 18causes the bags 18 to be somewhat stiffer or rigid. Hence, even thoughthe bags 18 are made from a flexible material, they are self supportingwhen inflated. Both the nozzle members 26 and bags 18 may be of the typedisclosed in the reference '592 patent, along with the air distributor.The bags 18 are pivotally connected to the air distributor plenum 14 bymeans as commonly known in the art.

The horizontally extending bags 18b include a reinforcing rod 28pivotally connected to the plenum 14 by fasteners 30 at a first endthereof, and extending along the longitudinal length of the bag 18b andis received within a loop 32 attached to the bag 18. The verticallyextending bags 18a hang from the plenum 14.

The apparatus 10 includes actuator means 34 connected between thedistributor plenum 14 and the bag 18 for moving the bag 18 toward andaway from the vehicle. The actuator means 34 includes link means 36connected to the bag 18 for controlling movement thereof, and retractingmeans 38 connected to the link means 36 and responsive to a controlsignal for actuating the link means 36 to position the bag 18 apredetermined distance from the vehicle. Control means 40 is operativelyconnected to the actuator means 34 for receiving a control signal tocontrol movement of the actuator means 34.

More specifically, the retraction means 38 includes a motor 42, and thelink means 36 comprises a flexible rope or cord. The motor 42 isoperatively connected to a spool 44 for controlling rotation of thespool 44 in a first direction to retract the bag 18 and in a seconddirection allow extension of the bag 18. The cord 36 is wrapped aboutthe spool 44 so that when the spool rotates in a first direction thecord 36 is wrapped further upon itself on the spool 44 to therebyshorten the length of the cord 36 and to retract the bag 18 away fromthe vehicle. When the spool 44 is released and allowed to rotate in thesecond direction, the gravitational pull on the bag 18 will unwind thecord 36 from the spool 44 allowing the bag 18 to fall toward thevehicle.

The cord 36 is removably attached to the bag 18 and spool 44 byreleasable means. The releasable means includes bag separable means 46generally comprised of a bag nylon loop 45 attached to the bag 18, bystitching or other permanent connection. The cord 36 is attached to thebag nylon loop 45 by a releasing loop 47 with a hook and pile surfaces48, 50, such as Velcro™, therebetween. The cord 36 is secured directlyto the releasable loop 47 in the vertical hanging bags 18a, and issecured through a pulley 37, which is in turn connected to the loop 47,in the horizontal bags 18b. The hook/pile material 48, 49 is fixedlyattached to the ends of the releasable loop 47 by sewing, etc. The twohalves of hook/pile material 48, 50 are secured to one another tomaintain the cord 36 connected to the bag 18 under normal operating andtensioning operation. If by accident, a vehicle catches the cord 36,i.e., by an antenna or other protrusion from the vehicle, as the vehicledraws away from the bag 18, the cord 36 will be disconnected from thebag 18 at the separable connection 46, i.e., the loop 47 will separatefrom the bag loop 45 at the hook/pile surface 48, 50. This will protectany further damage to the bag 18 or motor 42.

The releasable means also includes releasing connection means 52. Thecord 36 is attached to the spool 44 by the releasing connection means52. The releasing connection means 52 comprises an aperture 54 withinthe spool 44 extending radially therein for approximately three-quartersof the diameter. A longitudinal bore 55 extends from the end of thespool 44 to the aperture 54. The bore 55 receives a ball 56 biased by aspring 57 and supported in the bore 55 by a plug 58. The bore 55 narrowsat the juncture with the aperture 54 to allow the ball 56 to extendpartially, i.e., one-third, into the aperture 54. The cord 36 isgenerally a nylon rope, and includes on its end a ball and shank 59. Thecord 36 extends through an aperture 60 in the ball and shank 59 which iscrimped thereof, and the end of the cord 36 is melted to form a head tosecure the core 36 to the ball and shank 59. The ball and shank 59 isinserted within the spool aperture 54 and secured by the biased ball 56.In the case that either the cord 36 or bag 18 is ripped off by a vehicleor other means, the cord 36 will unwind from the spool 44. Uponproduction of a predetermined force greater than the force created bythe weight of the bag 18, the ball and shank 59 will pull out from theball 56 allowing release of the cord 36 therefrom.

As illustrated in FIG. 4, the motor 42 is secured to a motor mountingplate 62, which is in turn secured to the plenum 14. A motor housingcover 64 is placed over the motor 42 on the motor mount 62 formaintaining same clean of contaminants. The spool 44 includes a secondbore 63 in a second end thereof to fixedly receive a shaft of the motor42, secured by a fastener or pin through a second radial aperture 65. Inthe horizontal bags 18b, the cord 36 is looped through the pulley 37 andconnected to the motor housing. In the vertical bags 18a, the cord 36 isdirectly attached to the loop 47.

The control means 40 includes a plurality of sensor means 66 fixedlyconnected to the bags 18 for sensing the distance to the vehicle and forproducing a sensed signal. The sensor means 66 includes supervisorsensor means 68 which provides the main control of the sensors on thebag 18, and satellite sensor means 70 which is controlled by thesupervisor sensor 68 and provides remote sensing on the same bag 18 asits respective supervisor sensor 68. The sensor means 68, 70 includehousing means 72, 74 for housing the electronic circuits as subsequentlyexplained. Each of the sensor means 68, 70 include a sensor face 76, 78which is generally in the direction of the nozzle 26 and toward thevehicle. The sensor face 76, 78 includes a transmitter aperture 80, 81and two receiver apertures 82, 83. The transmitter aperture 80, 81 iscentered between the two receiver apertures 82, 83 with spacingtherebetween. Projecting from the sensor face 76 between the apertures80-83 are a plurality of barriers 84, 85 for blocking transmission fromthe transmitter directly to reception by the receiver. The barriers 84,85 are generally in the form of a saw tooth having its angular facedirected toward the transmitter aperture 80, 81. There are generallyfive saw teeth 84, 85 spaced the length of a waveform apart from oneanother between the aperture 80-83. The saw teeth 83, 84 extendtransverse to the line between the apertures 80-83. The supervisorsensor means 68 includes a generally rectangular shaped flexible plasticbox 86 having a pair of flanges 88 extending therefrom with apertures 90therein for receiving a fastener in order to be fastened to the bag 18or nozzle 26. The front face 76 forms one of the sides of therectangular housing 86 and is connected on one longitudinal side thereofproviding a hinge 92. The hinge 92 allows the front or sensor face 76 tobe angled with respect to the remainder of the housing 86 once installedupon the bag 18 to provide proper angular orientation for directiontoward the vehicle. The satellite sensor means 70 includes a generallytriangular housing 94 having two enclosed sides 93, 95 forming rightangles, and the front face 78 forming the third side. The front face 78is fixedly connected to one of the sides to form a hinge 93 as in thesupervisor means 68. The housing 94 includes two ends having flangesextending therefrom for receiving fasteners for securing to the nozzle26. Once the sensor faces 76, 78 are positioned, the seams of thesensors 66 are sealed with an epoxy, such as super glue of the type3M-CA40. The housings 86, 94 may be comprised of a urethane material,such as Hytrel by DuPont.

The control means 40 is generally indicated in FIG. 6 and controls theactuator means 38 and the distance of the bag 18 from the vehicle. Thecontrol means 40 is generally comprised of timing means 102, supervisorymeans 104, sensing means 106, and motor means 108. The timing means 102generally provides the timing information for all of the sensor means 66and control means 40 for a single dryer apparatus 10. The supervisorymeans 104 provides the control for a single bag 18, i.e., only one eachbag 104, within the apparatus 10. The sensing means 106 is locatedwithin each sensor 66 and operates in conjunction with the supervisorymeans 104 for sensing the distance of a bag 18 from the vehicle. Aplurality of sensing means 106 may be used on each bag 18 within eachsensor means 66. The motor means 108 is responsive to the supervisorymeans 104 to control operation of the motor for retracting the bag 18when desired.

As illustrated in FIG. 6, the timing means 102 receives an analogvoltage signal, i.e., 24 vac from a transformer, and includes clip means110 for clipping the amplitude to a predetermined amplitude of theanalog signal. The clipping means 110 produces an amplitude controlledsignal which is received by a zero crossing detector 112 which detectseach zero crossing to produce a positive going pulse. The pulse isreceived by a pulse inverter means 114 which inverts the pulse producinga negative going pulse at 120 Hz as a timing signal. The inverted pulsesignal is received by the supervisory means 104.

The supervisory means 104 includes oscillating means 116 for producing aclock signal of 640 KHz. A ripple counter 118 receives the clock signaland the timing signal comprising the inverted pulse to produce atransmit signal and a reset signal. The counter 118 produces thetransmit signal at 40 KHz for eight pulses for each timing signal pulseand the reset signal is produced at a divide by 16 output wherein apulse is produced for the reset signal for the last 4 of the 8 pulses ofthe transmit signal. The supervisory means 104 includes an integrator120 for receiving the reset signal and initiating at distance ramp whichestablishes amplitude vs. time. Also included in an echo detector 122for receiving the reset signal to reset itself to wait and detect theecho and a receiver signal representing the echo to produce a set signalupon reception of the receiver signal. A pulse formatter 124 formats theoutput of the echo detector 122 to produce the set signal in the form ofa pulse. Distance means 126 receives the set signal and compares same tothe distance ramp to produce a control signal indicative of distance ofthe bag 18 from the vehicle. The distance ramp is initiated at the timeof the transmission of pulses to the vehicle and starts high anddecrements magnitude or voltage proportional to time. The set signalrepresents the time for reception of the reflected transmissions, andtherefore comparison to the ramp is indicative of the time delay.

The sensing means 106 includes driver means 128 for receiving thetransmit signal and producing ultrasonic transmissions throughtransmitter 130 of the eight pulses it receives at the 40 KHz. Thesensing means 106 also includes receiver oscillator means 132 forproducing a receiver timing signal at a similar 40 KHz. The receiverlooks during a two second window to receive the echo. The receivertiming signal is amplified by amplifier 134 and communicated to a tonedetector 136. The tone detector is tuned to 40 KHz, the same as thetransmitted signal. Upon detection of the tone, the tone detector 136produces the receiver signal to the echo detector 122 to initiate thedistance sensing.

The motor means 108 receives the control signal by a unity gainamplifier 138 which is then sent to an offset inverting amplifier 140.The inverting amplifier 140 produces the magnitude distance signal. Alsoincluded is a motor current monitor 142 for monitoring the current drawnby the motor 42. A current integrator 144 receives the current magnitudefrom the motor current monitor 142 and produces a minimum signal whenthe current is below a predetermined limit. O-ring means 146 receivesboth the magnitude distance signal and the minimum signal and passes thegreater of the two signals. The passed signal is amplified by a unitygain amplifier 148 and is communicated to drive means 150 to in turndrive the motor 142. The minimum signal is provided to maintain the cord36 taut.

The timing means 102 is generally positioned within a control box 152 ona beam member 16 of the apparatus 10. The supervisory means 104 iscontained within the supervisor sensor means 68 wherein only onesupervisor sensor means 68 and supervisory means 104 is included on eachbag 18. Generally, it is desirable to have more than one sensor means 66on each bag to ensure that the sensing means 66 will sense the vehicleirrespective of orientation of the bag 18 to the vehicle. Therefore, thesatellite sensor means 70 is utilized to supplement the supervisorsensor means 68 on the front and back sides of the nozzle 26. Both ofthe supervisor sensor means 68 and satellite sensor means 70 include thesensing means 106 therein. The satellite sensing means 70, which alsoincludes sensing means 106 therein, will receive all signals requiredand communicate the receiver signal to the supervisory means 104associated with the particular bag 18 thereon. The motor means 108 isplaced adjacent the motor 42 in the housing 64.

The bags 18 include at least one sensor means 66 positioned thereon, oneof which is the supervisor sensor 68. With regard to the overhead orvertical bags 18a, sensor means 66 are placed on both sides of thenozzle 26 as illustrated in FIG. 11. The supervisor sensor 68 is on thefront side and the satellite sensor 70 is on the rear side of the nozzle26. The left overhead bag 18a has the sensors 68, 70 located near thecenter of the nozzle 26, and the right overhead bag 18a has the sensors68, 70 located at the extreme left side of the nozzle 26 to compensatefor smaller width vehicles. The horizontal bags 18b has two frontsensors 66 aligned with the wheel well and mirror, and one rear sensor66. On the left side, the upper left bag 18b has one front and one rearsensor 66 and the lower bag 18b has two front and one rear sensor 66positioned as in the right side. All bags 18 have one supervisor sensor68 which is generally positioned on the front surface of the nozzle 26.

The back side 91 of the sensors 66 may have a rear flap 93 extendingthereagainst and fixedly attached to nozzle 26. The flap 93 ensures thatthe vehicle cannot catch on a sensor 66 when passing therethrough.

FIG. 7 illustrates the schematic diagram of the timing means 102, andwill be now described. The timing means 102 receives a 24 volt analogpower signal. It is to be understood that suitable voltage regulatorsmay be used to produce the other power levels indicated in theschematics. The analog power signal is received by the clipping means110 which comprises a resistor R1 in series with the power source andconnected to a pair of parallel opposite polarity diodes D1, D2 whichare connected to ground. A resistor R2 is connected to the diode D1, D2and to the noninverting input of operational amplifier 160 having itsinverting input grounded. The output signal is attenuated by capacitorC3 and a resistor R4 is connected to ground and to resistor R3 which isconnected to the zero crossing detector 112. The zero crossing detector112 comprises an operational amplifier 162 having its inverting inputconnected to resistor R3 and its noninverting input connected to groundwith feedback to the inverting input through reverse bias diode D3 toresistor R5 and through forward bias diode D4 through resistor R6. TheD3, R5 connection is connected to resistor R7 and connected to theinverting input of a second operational amplifier 164 wherein thenoninverting input is connected to the D4, R6 connection. Feedback isprovided through resistor R8 to the inverting input. The output of theoperational amplifier 164 is connected through resistor R9 producing thepositive going pulse upon each zero crossing of the analog signal. Thepulse invertor means 114 receives the positive going pulse to produce anegative or inverted pulse producing the timing signal. The pulseinverting means 114 comprises an operational amplifier 106 receiving thepositive going pulse at its noninverting inputs and has its invertinginput connected a voltage divider circuit comprising resistors R11 andR12. The output of the operational amplifier 166 is connected throughresistor R10 to a grounded reverse bias diode D5 and to drive atransistor Q1 at its base producing the timing signal at it collector.

FIG. 8 illustrates the schematic of the supervisor means 104. Theoscillator means 116 includes a crystal oscillator 168 connected betweentwo grounded capacitors C7, C8. Parallel with the crystal 168 is aresistor R19 and parallel therewith is invertor 170. The output of theinvertor 170 is connected through a diode D6 to resistor R18 to power,and to diode D7 to an invertor 172 to the timing signal. This producesthe clock signal of 640 KHz. The timing signal is received by a reversebiased diode D8 and connected through resistor R20 to power and to theinput of the ripple counter 118. The ripple counter 118 comprises aripple binary counter 174 of the type national semiconductor CD4020BCN.The ripple counter 174 receives at pin 10 the clock signal and at pin 11the timing signal. Pin 13 is connected through invertor 176 to diode D9to the clock signal. Power is supplied to pin 16 with a ground capacitorC9 and ground is provided at pin 8. The counter 174 produces thetransmit signal through resistor R21, which is also connected toresistor R22 to positive voltage. The pin 6 output produces the resetsignal.

The integrator means 120 receives the reset signal and comprises aresistor R23 connected to the base of transistor Q2 having its emittergrounded and its collector connected to voltage divider comprising R24to ground and R25 to voltage. The collector signal is received at theinverting input of an operational amplifier 178 having feedbacktherethrough through capacitor C10, with its noninverting inputconnected through resistor R26 to ground. The output of the operationalamplifier 178 produces the ramp signal.

The reset signal is also received by the echo detector means 122 whichcomprises a resistor R27 receiving the reset signal and connected toresistor R28 to power and the inverting input of operational amplifier180. The receiver signal is received by resistor R30 to power and byinvertor 182 through resistor R32 and to the noninverting input of theoperational amplifier 180. Feedback is provided through resistor R33 tothe noninverting input. The output of the operational amplifier 180 isconnected by resistor R34 to ground and invertor 184, through capacitorC11 with resistor R35 connected to power and to invertor 186 to thedistance means 126. The distance means 126 includes a sample/holdcircuit which receives both the set signal and the ramp signal forproducing an output indicative of the point on the ramp at theoccurrence of the set signal in time. The occurrence signal is sent to acurrent source 190 comprising an operational amplifier 192 receiving thesignal at its noninverting input and having its output driving the baseof transistor Q3 having its collector committed to power and its emitterconnected to resistor R37 and R38. Resistor R38 is connected to groundthrough resistor R39 and to the noninverting input of operationalamplifier 194 which has its inverting input connected to resistor R40 tothe control signal and having feedback through resistor R41 to theinverting input. The output of operational amplifier 194 is connectingto the inverting input of operational amplifier 192.

The sensing means 106 is more particularly illustrated in FIGS. 9 and11. The sensing means 106 includes transmitter means 200 (FIG. 11) forreceiving the transmit signal and comprises two drive operationalamplifiers 202, 204 wherein the first operational amplifier 202 receivespower at its inverting input and receives transmit signal at itsnoninverting input, and the second operational amplifier 204 isconfigured as the first with an output capacitor C12 at its output, bothconnected to an output transmitter 130. The transmitter 130 is located athe transmitter aperture 80, 81 in the sensor housing 68, 70. The sensoris of the type ultrasonic sensor MA series by MURATA MFG. CO. Thesensing means 106 also includes the receiver (FIG. 9). The receiverincludes the oscillator 132 comprising a crystal oscillator 206 parallelwith the grounded resistor R43, and connected to a series capacitor C13and to the base of transistor Q4. A resistive divider circuit comprisingresistors R46, R47 are connected at the base between power and ground.The collector is connected through resistor R44 to positive voltage andthe emitter is connected through parallel resistor capacitor R45, C14ground circuit. The emitter is connected to a parallel capacitor C15 forattenuation and to a coupling capacitor C16, comprising the amplifier132. Capacitor C16 is connected to the input of the tone detector means136. The tone detector means 136 comprises a tone decoder 208 of thetype of National Semiconductor LMC567, low power tone decoder. The tonedetectors 208 require so many cycles to be detected to lock on thephase. Two capacitors C17, C18 are provided as an output filter and loopfilter, and power and a capacitor C19 are provided at pin 4 as a voltagesource. The timing of the decoder 208 is provided at pins 5, 6 and 7through variable resistor R46 and capacitor C20. Output is provided atpin 8 providing the receiver signal. When the tone is detected, thereceive signal goes to ground. As previously indicated, each of thesensing means 66 comprises the two receiver means 132 with the singletransmitter 200. Therefore, the second receiver 132' is configuredidentical to the first receiver wherein primed numerals indicate similarparts. Both of the signals from the tone detectors 208, 208' arecombined to provide the receiver signal.

The motor means 108 is specifically illustrated in FIG. 10. The controlsignal is received by the unity gain amplifier 138 which comprises aparallel grounded capacitor C21 and resistor R47 on the input line and aseries resistor R48 to the inverting input of operational amplifier 210having its noninverting input connected to a voltage divider comprisingresistors R49 and R50. Feedback to the inverting input is providedthrough resistor R51. The output of operational amplifier 210 isprovided through resistor R52 to the inverting input of operationalamplifier 212 having its noninverting input connected to a variableresistor R53. Feedback to the inverting input is provided throughresistor R54. The output of operational amplifier 212 is fed through adiode D12 providing the magnitude distance signal. The operationalamplifier 212 comprises the inverting amplifier means 140. The motorcurrent monitoring means 142 comprises a resistor R56 for monitoring thecurrent draw on the motor which is connected through the resistor R57 tothe inverting input of operational amplifier 214 to comprise the minimumcurrent integration means 144. The noninverting input is connected to avariable resistor R58 and fixed resistor R59. Feedback is provided tothe inverting input through capacitor C22. The output of the operationalamplifier 214 through diode D13 provides the minimum signal. The diodeD12 and D13 provide for an O-ring or combining circuit 146 wherein thehighest signal is sent to the unity gain amplifier means 148. The unitygain amplifier means 148 comprises an operational amplifier 216 havingits noninverting input connected to the resistor R60 receiving the Or'dsignal and its inverting input connected in unity gain follower feedbackto the emitter of a transistor Q5. The output of the operationalamplifier 216 is fed through resistor R61 to the base of transistor Q5.The collector of transistor Q5 is connected through resistor R62 topower and to the drive transistor 150. The drive transistor 150generally comprises a MOSFET wherein the emitter of transistor Q5 isconnected to the gate of MOSFET 150. The source is connected to powerand the gate is connected to the motor 42.

In operation, when a vehicle is passing through the apparatus, the airdistributor 12, 14 operates and the timing means 102 is powered along ofthe control means 40. The timing means 102 produces a timing signalwhich is received by the supervisory means 104. The supervisory means104 produces the transmits signal which is received by the sensors 66for periodic transmission. The reset signal is produced periodically andupon reception by the receiver, the receiver signal is received by theecho detector 122. No further operation takes place until the echodetector 122 receives the receiver signal. Upon a sensor means 66 havinga surface of the vehicle passing within a predetermined distance, theecho signal is produced which in turn will control the height of therespective bag 18. When a reflection is received, the supervisory means104 detects the distance. The motor means 108 receives the distance andwhen less than a predetermined amount, energizes the motor 42 tomaintain the predetermined distance. The motor 42 is released ordeenergized when greater than the predetermined distance, wherein theweight of the bag 18 unwinds the cord 36 from the motor 42.

When the sensor signal is low, the motor means 108 maintains a minimumcurrent to the motor 42 to hold the core 46 taut. This beneficial in thecase that a person retracts the bag manually or other means, the motor42 will also retract the cord 36 to prevent any type of entanglementwith other obstacles. Upon release of the bag 18, the bag 18 will beallowed to fall to its original position or most extended position.

The supervisory means 104 on each bag receives all of these sensorsignals and controls the motor means 108 in response thereto. Therefore,each of the bags 18 is controlled independently of the other bag. Eachbag 18 will maintain a predetermined distance to the vehicle andobstacles detected in the path without contact thereof.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims whereinreference numerals are merely for convenience and are not to be in anyway limiting, the invention may be practiced otherwise than asspecifically described.

What is claimed is:
 1. An apparatus for stripping fluid from the surfaceof an object as the object is conveyed relative to the apparatus along apath comprising:an air distributor (14); at least one bag (18) havingfirst and second ends, said first end supported by said air distributor(14) about the path of the surface for receiving air under pressure fromsaid air distributor (14), said second end including a nozzle (26) fordirecting air toward the surface to strip fluid from the surface;actuator means (34) connected between said distributor (14) and said bag(18) for moving said first end of said bag (18) toward and away from thesurface; control means (40) operatively connected to said actuator means(34) for receiving a control signal to control movement of said actuatormeans (34); said actuator means (34) including a link member (36)operatively connected to said bag for controlling movement of saidsecond end of said bag and retracting means (38) connected to said linkmember (36) and responsive to said control signal for actuating saidlink member (36) to position the second end of said bag (18) apredetermined distance from the surface; releasable means (46, 52)operatively connected between said link member (36) and at least one ofsaid retracting means (38) and said bag for allowing separation of saidlink member in response to a predetermined force at said releasablemeans (46, 52).
 2. An apparatus as set forth in claim 1 furthercharacterized by said releasable means (52) including releasingconnection means operatively connected between said link member (36) andsaid actuator means (38) for allowing separation of link means (36) fromsaid actuator means (38) in response to a predetermined force on saidlink member (36) and at a predetermined distance of said second end fromthe surface.
 3. An apparatus as set forth in claim 2 furthercharacterized by said retracting means (38) including a rotatable spool(44), said releasable means (32) including an enlarged ball (59)attached to said link member (36) and an aperture (54) within said spool(44) for receiving said enlarged ball (59) and means for biasing saidenlarged end within said aperture.
 4. An apparatus as set forth in claim3 further characterized by said releasable means comprising separablemeans (46) operatively connected between said link member (36) and saidbag (18) for allowing said link member (36) to separate from said bag(18) in response to a predetermined force on said bag.
 5. An apparatusas set forth in claim 4 further characterized by said separable means(46) including a loop having two ends and connected between said bag(18) and said link member (36) and having separable hook and pilematerial attached at said two ends for allowing separation of said endsand separation of said bag (18) and link member (36) in response to saidpredetermined force.
 6. A method of stripping fluids from the surface ofan object as the object is conveyed relatively along a path includingthe steps of:directing air under pressure through a nozzle; detectingthe distance of the nozzle from the surface; controllably retracting andextending the nozzle by a link member connected to the nozzle inresponse to the detection, and releasing the control of the nozzle bydisconnecting the link member in response to a predetermined forceapplied against the nozzle.